With a wide spread use of Global Positioning System (GPS), the location of a target with a GPS receiver in an open area can be easily be traced. However, when the target is in an urban area surrounded by tall buildings, the GPS receiver is unable to provide an accurate estimation of the location of the target as the GPS signals are weakened or blocked.
In an indoor situation, the GPS signals are attenuated and the location of the target cannot be tracked using the GPS receiver. This poses a problem for users who want to track a target in an indoor situation such as an office building, car park etc. There is no indoor tracking or positioning system that allows high accuracy of tracking a target.